The present disclosure generally relates to the field of signal analysis in an aircraft. Further, the present disclosure relates to the field of using basis functions for signal analysis in an aircraft. Basis functions may be generally used to analyze signals (e.g., images) obtained by an aircraft and/or ground station. Some systems use a dictionary of basis functions for signal analysis. In such systems, the dictionary is typically fixed, i.e., the basis functions in the dictionary are pre-set and are not based on any signal analysis of the current signal.